Test-Driven Development with Qt and KDE Kevin Ottens Kevin Ottens - - PowerPoint PPT Presentation

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Test-Driven Development with Qt and KDE

Kevin Ottens

Kevin Ottens — Test-Driven Development with Qt and KDE 1/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Introduction

Goals Discover the possibilities of the Qt and KDE frameworks Practice Test-Driven Development (TDD) Method Putting in place the project infrastructure Developing the GUI part of the application Show the advantages of the model/view split available in Qt Apply TDD on the application model development

Kevin Ottens — Test-Driven Development with Qt and KDE 2/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 3/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 4/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

CMake and first source file

Create a main.cpp file containing the main() function, only displaying a debug message; Create a file CMakeLists.txt for this project named spreadsheet; Create the build directory, and compile the project using CMake.

Kevin Ottens — Test-Driven Development with Qt and KDE 5/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

KApplication and first display

Create a KAboutData and use it with KCmdLineArgs::init() Create a KApplication and an empty QWidget as main window

Kevin Ottens — Test-Driven Development with Qt and KDE 6/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Toward a standard window

Add a class SpreadSheetMainWindow which inherits from KXmlGuiMainWindow, use it as main window; Put in place the following actions: New, Open, Save, SaveAs, Quit, Cut, Copy, Paste Add one slot by action in SpreadSheetMainWindow (except for Quit which will be connected to the close() slot of the window. Hint : Use the KActionCollection and the method setupGUI() provided by KXmlGuiMainWindow.

Kevin Ottens — Test-Driven Development with Qt and KDE 7/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Spreadsheet interface

Add a QTableWidget as the window central widget (force and initial size of 100 by 100); Add the actions Cut, Copy and Paste in the contextual menu of QTableWidget; Add two QLabel to SpreadSheetMainWindow and position them in the status bar (they’ll be used to indicate the coordinates of the current cell, and the formula contained). Important in the following: In SpreadSheetMainWindow, the pointer to the QTableWidget will be of type QTableView*.

Kevin Ottens — Test-Driven Development with Qt and KDE 8/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 9/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Implementing the base features

Until now, we only put building blocks together No test written yet Here will develop the GUI based base features Our first unit test will be written nonetheless

Kevin Ottens — Test-Driven Development with Qt and KDE 10/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Populate the table

Hardcode the following dataset for the table initialization: William Adama 1947-02-24 Saul Tigh 1949-03-22 Lee Adama 1973-04-03 Kara Thrace 1980-04-08 Laura Roslin 1952-04-28 Gaius Baltar 1971-06-04

Kevin Ottens — Test-Driven Development with Qt and KDE 11/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Location

Write a test for a

static QString locationFromIndex(int row, int column) which converts (0, 0) in A1, (0, 1) in B1 and so on;

Implement the method while increasing the amount of data for the test; Implement the necessary to update the status bar depending on the current cell, we’ll use locationFromIndex().

Kevin Ottens — Test-Driven Development with Qt and KDE 12/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Manipulate data

Implement Copy, Cut and Paste for one cell at a time; Extand it for contiguous cell zones (requires to force the behavior of selections in the view), pasting starts at the current cell.

Kevin Ottens — Test-Driven Development with Qt and KDE 13/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 14/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

MVC for our spreadsheet

We’ll now create our own data model for this spreadsheet. The main features will be implemented thanks to this model. Here, the TDD approach will be fully applied.

Kevin Ottens — Test-Driven Development with Qt and KDE 15/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Model/view approach setup

Implement a test for a new class SpreadSheetModel inheriting from QAbtractTableModel, during its creation such a model will contain

• nly empty cells and have a size of 216 columns by 216 lines;

Create a new class SpreadSheetModel which pass the previous test; Replace the QTableWidget of exercise 8 with a QTableView, give it an empty SpreadSheetModel during its creation. Information: rowCount() and columnCount() must return 0 when the QModelIndex given as parameter is valid. For more information refers to the documentation of QAbstractTableModel.

Kevin Ottens — Test-Driven Development with Qt and KDE 16/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Ensure lines and columns labelling

Write the unit test for a

static QString SpreadSheetModel::rowNameFromIndex(int) verify that we obtain "1" for 0, "2" for 1, "10" for 9, and so on;

Write the method QString rowNameFromIndex(int); Write the unit test for a

static QString SpreadSheetModel::columnNameFromIndex(int) verify that we obtain "A" for 0, "B" for 1, "Z" for 25, "AA" for 26, "BA" for 52, and so on;

Write the method QString columnNameFromIndex(int); Overload headerData() in SpreadSheeModel to use the static methods freshly implemented... hey! the tests first; Modify the method locationFromIndex() of SpreadSheetMainWindow to eliminate the code duplication. Information: Latest modification done without modifying any test, you made your first refactoring avoiding regressions.

Kevin Ottens — Test-Driven Development with Qt and KDE 17/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Now, the questions will only be the unit tests that the model must pass.

Kevin Ottens — Test-Driven Development with Qt and KDE 18/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Store text

void SpreadSheetTest::testThatTextIsStored() { SpreadSheetModel m; QModelIndex index = m.index(21, 0); m.setData(index, "A string"); QCOMPARE(m.data(index).toString(), QString("A string")); m.setData(index, "A different string"); QCOMPARE(m.data(index).toString(), QString("A different string")); m.setData(index, ""); QCOMPARE(m.data(index).toString(), QString("")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 19/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that many cells exist

void SpreadSheetTest::testThatManyCellsExist() { SpreadSheetModel m; QModelIndex a = m.index(0, 0); QModelIndex b = m.index(23, 26); QModelIndex c = m.index(699, 900); m.setData(a, "One"); m.setData(b, "Two"); m.setData(c, "Three"); QCOMPARE(m.data(a).toString(), QString("One")); QCOMPARE(m.data(b).toString(), QString("Two")); QCOMPARE(m.data(c).toString(), QString("Three")); //=>

Kevin Ottens — Test-Driven Development with Qt and KDE 20/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that many cells exist

//=> m.setData(a, "Four"); QCOMPARE(m.data(a).toString(), QString("Four")); QCOMPARE(m.data(b).toString(), QString("Two")); QCOMPARE(m.data(c).toString(), QString("Three")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 21/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Store numeric data

void SpreadSheetTest::testNumericCells() { SpreadSheetModel m; QModelIndex index = m.index(0, 20); m.setData(index, "X99"); // String QCOMPARE(m.data(index).toString(), QString("X99")); m.setData(index, "14"); // Number QCOMPARE(m.data(index).toString(), QString("14")); QCOMPARE(m.data(index).toInt(), 14); //=>

Kevin Ottens — Test-Driven Development with Qt and KDE 22/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Store numeric data

//=> // Whole string must be numeric m.setData(index, "99 X"); QCOMPARE(m.data(index).toString(), QString("99 X")); bool ok; m.data(index).toInt(&ok); QVERIFY(!ok); m.setData(index, " 1234 "); // Blanks ignored QCOMPARE(m.data(index).toString(), QString("1234")); QCOMPARE(m.data(index).toInt(), 1234); m.setData(index, " "); // Just a blank QCOMPARE(m.data(index).toString(), QString(" ")); } Hint : Add the asserts one by one.

Kevin Ottens — Test-Driven Development with Qt and KDE 23/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Access to the original data for editing

void SpreadSheetTest::testAccessToLiteralForEditing() { SpreadSheetModel m; QModelIndex index = m.index(0, 20); m.setData(index, "Some string"); QCOMPARE(m.data(index, Qt::EditRole).toString(), QString("Some string")); m.setData(index, " 1234 "); QCOMPARE(m.data(index, Qt::EditRole).toString(), QString(" 1234 ")); m.setData(index, "=7"); QCOMPARE(m.data(index, Qt::EditRole).toString(), QString("=7")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 24/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 25/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Add the support for formulas

It is wise to add asserts of each proposed test one by one Or to add more tests... It depends on your confidence level concerning formulas processing

Kevin Ottens — Test-Driven Development with Qt and KDE 26/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Formulas support basics

SpreadSheetTest::testFormulaBasics() { SpreadSheetModel m; QModelIndex index = m.index(2, 10); m.setData(index, " =7"); // note leading space QCOMPARE(m.data(index).toString(), QString("=7")); QCOMPARE(m.data(index, Qt::EditRole).toString(), QString(" =7")); m.setData(index, "=7"); // constant formula QCOMPARE(m.data(index).toString(), QString("7")); QCOMPARE(m.data(index, Qt::EditRole).toString(), QString("=7")); // Adding intermediate tests here to guide you is fine // Go ahead! //=>

Kevin Ottens — Test-Driven Development with Qt and KDE 27/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Formulas support basics

//=> m.setData(index, "=(7)"); // parenthesis QCOMPARE(m.data(index).toString(), QString("7")); m.setData(index, "=(((10)))"); // more parenthesis QCOMPARE(m.data(index).toString(), QString("10")); m.setData(index, "=2*3*4"); // multiply QCOMPARE(m.data(index).toString(), QString("24")); m.setData(index, "=12+3+4"); // add QCOMPARE(m.data(index).toString(), QString("19")); m.setData(index, "=4+3*2"); // precedence QCOMPARE(m.data(index).toString(), QString("10")); //=>

Kevin Ottens — Test-Driven Development with Qt and KDE 28/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Formulas support basics

//=> m.setData(index, "=5*(4+3)*(((2+1)))"); // full expression QCOMPARE(m.data(index).toString(), QString("105")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 29/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Error management

void SpreadSheetTest::testFormulaErrors() { SpreadSheetModel m; QModelIndex index = m.index(0, 0); m.setData(index, "=5*"); QCOMPARE(m.data(index).toString(), QString("#Error")); m.setData(index, "=((((5))"); QCOMPARE(m.data(index).toString(), QString("#Error")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 30/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Minus, divide, negate

The client notices that he forgot to ask for the support of the minus, divide and negate operators in formulas. You now have to add them: Add tests for minus and then implement Add tests for divide and then implement Add tests for negate and then implement

Kevin Ottens — Test-Driven Development with Qt and KDE 31/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 32/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that a reference works

void SpreadSheetTest::testThatReferenceWorks() { SpreadSheetModel m; QModelIndex a = m.index(0, 0); QModelIndex b = m.index(10, 20); m.setData(a, "8"); m.setData(b, "=A1"); QCOMPARE(m.data(b).toString(), QString("8")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 33/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that changes propagate

void SpreadSheetTest::testThatChangesPropagate() { SpreadSheetModel m; QModelIndex a = m.index(0, 0); QModelIndex b = m.index(10, 20); m.setData(a, "8"); m.setData(b, "=A1"); QCOMPARE(m.data(b).toString(), QString("8")); m.setData(a, "9"); QCOMPARE(m.data(b).toString(), QString("9")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 34/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that formulas are recalculated

void SpreadSheetTest::testThatFormulasRecalculate() { SpreadSheetModel m; QModelIndex a = m.index(0, 0); QModelIndex b = m.index(1, 0); QModelIndex c = m.index(0, 1); m.setData(a, "8"); m.setData(b, "3"); m.setData(c, "=A1*(A1-A2)+A2/3"); QCOMPARE(m.data(c).toString(), QString("41")); m.setData(b, "6"); QCOMPARE(m.data(c).toString(), QString("18")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 35/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that changes propagate on several levels

void SpreadSheetTest::testThatDeepChangesPropagate() { SpreadSheetModel m; QModelIndex a1 = m.index(0, 0); QModelIndex a2 = m.index(1, 0); QModelIndex a3 = m.index(2, 0); QModelIndex a4 = m.index(3, 0); m.setData(a1, "8"); m.setData(a2, "=A1"); m.setData(a3, "=A2"); m.setData(a4, "=A3"); QCOMPARE(m.data(a4).toString(), QString("8")); m.setData(a2, "6"); QCOMPARE(m.data(a4).toString(), QString("6")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 36/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify the use of cells in several formulas

void SpreadSheetTest::testThatFormulasWorkWithManyCells() { SpreadSheetModel m; QModelIndex a1 = m.index(0, 0); QModelIndex a2 = m.index(1, 0); QModelIndex a3 = m.index(2, 0); QModelIndex a4 = m.index(3, 0); QModelIndex b1 = m.index(0, 1); QModelIndex b2 = m.index(1, 1); QModelIndex b3 = m.index(2, 1); QModelIndex b4 = m.index(3, 1); //=>

Kevin Ottens — Test-Driven Development with Qt and KDE 37/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify the use of cells in several formulas

//=> m.setData(a1, "10"); m.setData(a2, "=A1+B1"); m.setData(a3, "=A2+B2"); m.setData(a4, "=A3"); m.setData(b1, "7"); m.setData(b2, "=A2"); m.setData(b3, "=A3-A2"); m.setData(b4, "=A4+B3"); QCOMPARE(m.data(a4).toString(), QString("34")); QCOMPARE(m.data(b4).toString(), QString("51")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 38/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Verify that the circular references give an error

void SpreadSheetTest::testCircularReferences() { SpreadSheetModel m; QModelIndex a1 = m.index(0, 0); QModelIndex a2 = m.index(1, 0); QModelIndex a3 = m.index(2, 0); m.setData(a1, "=A1"); m.setData(a2, "=A1"); m.setData(a3, "=A2"); QCOMPARE(m.data(a1).toString(), QString("#Error")); m.setData(a1, "=A3"); QCOMPARE(m.data(a1).toString(), QString("#Error")); }

Kevin Ottens — Test-Driven Development with Qt and KDE 39/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 40/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

GUI cleanup

If not done yet, remove the initialization of the table which was implemented previously If necessary, modify Cut, Copy and Paste so that they recopy formulas and not results; Add a test to ensure that the status bar displays the formula of the current cell, not its value; Add the code necessary to make the test pass. Hint: Use the parent/child relationship of QObject and its name property.

Kevin Ottens — Test-Driven Development with Qt and KDE 41/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

To go further...

Some aspects are ignored in this training, and it would be necessary to see them to complete the application : saving, for this it’d be required to take a look at QIODevice, KIO::NetAccess and KFileDialog; some small display issues tied to the lack of events emitted by the model, then it’d be necessary to take care of the QAbstractItemModel signals like dataChanged(); function support in formulas; and probably more...

Kevin Ottens — Test-Driven Development with Qt and KDE 42/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Outline

1 Project setup and Main window 2 Implementing the base features 3 MVC for our spreadsheet 4 Add the support for formulas 5 Implement the support for references in formulas 6 Finalizing the application 7 Conclusion

Kevin Ottens — Test-Driven Development with Qt and KDE 43/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Conclusion

Facts We got a decent spreadsheet for the given effort The application is 433 lines of code, and only has two classes; Our tests are 368 lines of code, and they cover our model as well as a part of the GUI (we could have made more); We progressed by small modifications by adding a constraint at a time. What have you learned? How to apply test-driven development and its advantages Now you can add complex features progressibely and avoiding regressions Better understand the features provided by Qt and KDE How to obtain a lot of results with a few lines of code

Kevin Ottens — Test-Driven Development with Qt and KDE 44/45

Outline Main window Base features MVC Formulas References in formulas Finalizing Conclusion

Questions?

Kevin Ottens

ervin@kde.org

Kevin Ottens — Test-Driven Development with Qt and KDE 45/45